Long range objectives are to define reactions which are required for synapse formation or for regulation of transmission of information across the synapse. BIBLIOGRAPHIC REFERENCES: Christian, C., Nelson, P., Peacock, J. and Nirenberg, M.: Synapse formation between two clonal cell lines. Science 196: 995-998, 1977. Chalazonitis, A., Minna, J.D. and Nirenberg, M.: Expression and properties of acetylcholine receptors in several clones of mouse neuroblastoma x L cell somatic hybrids. Exp. Cell. Res. 105: 269-280, 1977.